The present invention relates generally to the field of vehicle restraint systems including belts for securing an occupant to a seat.
School bus passenger seats usually do not employ active restraint safety devices, but instead rely on a passive restraint seat design. School bus passenger seats are built to specifications conforming to the safety standards set by the National Highway Traffic Safety Administration, DOT. These are codified as 49 C.F.R. Ch.V, xc2xa7571.222, Standard No. 222, and require that the seat back bend or deflect forward when a force is applied to the rear of the seat back. The code further specifies that 4000 W inch-pounds of energy must be absorbed within a maximum forward deflection of the seat back of 14 inches and 2800 W inch-pounds be absorbed within a maximum rearward deflection of the seat back of 10 inches where W represents the number of seating positions for which the seat is designed. 49 C.F.R., Ch.V, xc2xa7571.222, S5.1.3-5.1.4. The code specifies a passive restraint system, and does not require any sort of active restraints, such as a two-point passenger restraining lap belt or a three-point passenger restraining lap belt and torso harness combination. Children riding the school bus are protected in head-on collisions by the seat back in front of them deflecting forward and absorbing some of their forward momentum.
Vehicles with deforming or deflecting seats provide special problems regarding the integration of active restraint seat belt systems. Passive restraint systems are designed to protect a passenger who has been thrown forward by having the impacted seat back deflect upon impact of the thrown passenger and absorb some of their momentum. In a school bus seat combining active and passive restraint systems, both of the restraint systems have to be able to perform their functions and the seat must still conform to the regulations set forth in 49 C.F.R.
In order to combine a deforming or deflecting seat with a seatbelt, we have mounted the belt to a portion of the seat which slides forward upon crash and away from the forwardly deforming seat back. Thus, the seat conforms with the aforementioned deflecting requirements but in addition includes a belt for securing the occupant to the seat. In one embodiment, a plurality of seats with seat belts are slidably mounted to the same seat frame and independently of each other slide forward upon crash. The U.S. Pat. No. 3,552,795 issued to Perkins et al discloses a seat having a seat portion and back portion slidable forward upon crash. The Perkins seat is not designed to provide an upright forwardly deforming seat back in addition to a seat slidable forward upon crash.
In the event a three-point seatbelt is to be utilized, it is necessary to provide a shoulder belt guide that will move with the seat as the seat slides forward upon crash. Disclosed is a combination seat and seat back with a belt guide slideable as a unit from the main seat frame in turn having a deflectable seat back frame.
One embodiment of the present invention is a seat for a vehicle comprising a main frame mountable in a vehicle and having a seat supporting frame and an upright back-supporting frame. A plurality of adjacent vehicle seats are slidably mounted on the seat-supporting frame and each have a normal aft position and a crash forward position. The seats are movable from the normal aft position to the crash forward position independent of movement of the upright back-supporting frame. A plurality of seat belts are mounted to the vehicle seats and are slidably therewith.
It is an object of the present invention to provide a plurality of seats slidably mounted on the same seat frame with the seats movable forward upon crash independent of each other.
It is a further object of the present invention to provide a seat with a seat frame and a back frame connected together as a unit and slidably mounted to a base frame having an upright frame with the seat movable in the forward direction upon crash independent of movement of the upright frame.
Related objects and advantages of the present invention will be apparent from the following description.